Automatic control mechanism



June 2, 1936. A. c. DURDIN, JR 2,043,096

- AUTOMATIC CONTROL MECHANISM Original Filed Jan. 14, 1953 I l I F I I i 60 I I I l I I I I 5 i I 43 I I l I I l l l are FKDMPUMPA FRUM MP w 2 a a0 5 (#l# @2 i, =58 44 45 6 47 INVENTOR. flugusfus CDurd J/r ATTORNEY.

Patented June 2, 1936 UNITED STATES PATENT OFFICE sig'nor to Chicago Pump Company, Chicago, 111.. a corporation of Illinois Original application January 14, 1933, Serial No.

651,672, now Patent No. 1,982,578 dated November 27, 1934. Divided and this application August 18, 1934, Serial No. 740,382

11 Claims. (Cl. -40) This invention relates to automatic control mechanism, desirably for controlling electric motors, although its use is not limited thereto as it can be used for controlling the operation of a variety of mechanisms as will readily suggest themselves to persons skilled in this art. In its present application the control mechanism is shown in connection with an electric switch of the circuit transfer type, by means of which circuits for two motors are alternately transposed by the switch, whereby the motors are caused to operate in alternate sequence.

The subject matter of this specification has been divided out of my application for patent on automatic control mechanism for electric motors filed January 14, 1933 under Serial No. 651,672, upon which Letters Patent No. 1,982,578 were issued November 2'7, 1934.

In duplex pumping systems, which employ electric motor driven pumps, it is very desirable that the work of the two pumps be divided be tween them by causing automatic alternate operation of the pumps, and in accordance with the present invention, variation of pressure obtained at the two pumps has been utilized to actuate the mechanism for causing the alternate operation of the pumps. In the case of pressure pumps, the plus pressure at the discharge side thereof is utilized, whereas in the case of vacuum pumps, minus pressure at the intake side is used.

One object of the present invention is to provide novel means actuated by pressure, plus pressure or minus pressure, for setting a motion transmitting member into active position for transferring motion, such, for instance, as partially rotating 'the actuating element of an electric switch, whereby when the pressure is released, energy which has been stored up as a result of the actuation of the motion transferring member, is utilized to actuate the motion transmitting member and thereby actuate the actuating element of the switch. 7

Another object is to provide a pressure operated switch actuating device inwhich the motion transmitting means is common to two pressure actuated devices, each connected to a separate source of pressure supply, whereby the pressure developed at either source is utilized to set the motion transferring means into position for actuating an element. Other objects and advantages will occur in the course of this specification and with said objects and advantages in View, this invention consists in the several novel features hereinafter fully set forth and claimed.

The invention is clearly illustrated in the accompanying drawing, in which:

Fig. 1 is a view of the control mechanism embodying a simple form of the present invention, partly in side elevation and partly in vertical cross section taken on the line l--l of Fig. 2;

Fig. 2 is a front elevation of the control mechanism with the cover removed;

Fig. 3 is a detail vertical cross section taken on the line 3--3 of Fig.2;

Fig. 4 is a diagrammatic view illustrating the application of the-preferred form of the invention to a pumping system, and

Fig.5 is a perspective view of a group of star wheels used in the switch.

Referring to said drawing, which illustrates the invention applied to a duplex pumping system, the reference characters 'A, B designate the electric motors of a duplex installation of pumping units; A B designate the automatic starters for the motors; A B designate the pilot switches for closing the circuits and A B designate the pumps which are driven by the motors A, B and in the present application of the invention serve to pump liquid or other fluid to a storage tank (not shown). The pilot switches'A B, may be in the form of pressure, vacuum or float switches connected to and responsive to variations of pressure or water level in the tank, to or from which the liquid or fluid is pumped. In the present application of the invention, two pole pilot switches, in the form of pressure switches, are employed, connected to the storage tank into which the liquid or fluid is pumped by the pumps. Each pilot switch is adapted to close the circuits for both starters, and one pilot switch is set to close in advance of the other; whereby to start either one of the motors, the other pilot switch acting to close and start an idle motor in case the active one is incapable of performing all of the work. The motors are supplied by the feeder mains E, which in this instance, is shown as a three phase circuit. In the embodiment of the invention illustrated, the starter circuits con trolled by the pilot switches include branches Piping serving to transmit the liquid or fluid handled is shown at I ll, II, the pipe I0 being connected to the pump A and the pipe II to the pump B and when the circuit controlling mechanism is made responsive to plus pressure, the pipes II), II are connected to the discharge side of the pumps and lead to a storage tank or other receptacle or place to which the liquid or fluid is pumped. Check valves I0, are interposed in the pipes I0, I I adjacent the pumps.

Leading from valves l 2, connected to said pipes by Ts or otherwise, located between the pumps and check valves, are tubes l3, l4 that run respectively to the hubs l5, 5 of two pressure devices, here shown as comprising two diaphragms l1, l8 that are mounted on bars l9 secured to and supported by arms 3|! that project from a base 30 that is contained in a housing 3|, provided with a cover 32. The bars permit of the use of shims to effect proper adjustment of the diaphragms. The housing may of course be supported in any desirable manner.

The diaphragm I1 is provided with a cone or other stud 20 on its expansible side, which engages with a socket member 2| carried by a motion transmitting member such as yoke 22, and the diaphragm |8 also has a cone or stud 23 on its expansible side which engages with a socket member carried by a cross bar 25 of the yoke 22 whereby motion may be transmitted from either diaphragm to the yoke. In other words, pressure set up in either diaphragm will cause expansion of the diaphragm in which the pressure is set up and as a result the yoke or other motion transmitting device will be moved endwise, or upwards in the case of the one illustrated.

On the upper end of the yoke is a socket member 26 which receives one end of a compression spring 21 or other pressure means, the other end of which is received in a socket on the end of an adjustment screw 28 threadedly mounted in a bracket 29 that extends out from the base 30. A thumb wheel or knob 33 on the end of the adjustment screw 28 provides means whereby the latter may be easily manipulated.

The yoke 22 has a guide rod 34 extending from its end opposite the spring 21, which rod may be screwed into the end of the yoke and locked thereto by a lock nut 35. The guide rod 34 is guided for endwise movement in a bracket or arm 36, which projects out from the base 38, thus providing guiding means for the longitudinal movement of the yoke.

Upon the guide rod 34 is a collar 31, secured thereon as by a set screw 38, which collar carries a spring pressed pawl or detent 39 that engages with an actuated element, here shown as a ratchet wheel 40, rigidly mounted on a shaft 4|, journaled in bearing brackets 43 that extend out from the base 30. In the application of the inventlon here illustrated, the diaphragm, yoke, spring, guiderod, pawl and ratchet wheel provide pressure operated actuating means, responsive to pressure variations and acting to operate a switch as for instance a circuit transferring switch for effecting the alternate operation of the motors. Itwill be understood from the above that the reciprocating movements of the yoke 22 or other motion transmitting member 22 are translated into the rotary movement of the ratchet wheel and shaft. As illustrated, the yoke 22, rod 34 and detent 39 provide motion transmitting means for actuating the ratchet wheel 40, and in this connection the ratchet wheel 40 is an actuated element. The circuit transferring mechanism illustrated will now be described.

Rigidly mounted on the shaft 4| are star wheels or notched discs 44, 45, 4B, 41, desirably formed of fiber or other non-conducting material. Preferably the shaft 4| is square and engages in square holes in the ratchet wheel 40, and in the star wheels or notched discs 44, 45, 46, 41, said wheels being held in spaced relation by washers 42, or otherwise as desired. The star wheels serve to actuate contact members of the circuit transferring mechanism to control the circuits for two motors or other electric elements as will be presently described.

The notches of the two star wheels or notched discs 44, 41 are aligned, that is they occur in the same relationship, and the notches of the two star wheels 45, 46 are also aligned, but they occur intermediate the notches of the star wheels 44, 41, the purpose of which will be presently apparent. Desirably' there are as many teeth on the ratchet wheel 40 as there are combined notches and high parts on the star wheels, so that the step by step rotation of the ratchet wheel will cause step by step rotation of the star wheels, each step bringing notches into the position formerly occupied by the high parts and vice versa.

Mounted to ride upon the star wheels are movable spring pressed contact pieces 48, the terminal ends of which are arranged to enter the notches thereof, when they present themselves to the terminal ends. Each contact piece 48 cooperates with a stationary contact. piece 51 to intermittently close a break in an electric circuit as will be presently explained.

Desirably each contact piece 48 is mounted on a bracket 50 as by a lug 49 entering a hole in the bracket, and each contact piece is spring pressed against the associated star wheel by a spring 55 interposed between the contact piece and an adjustment nut 54, threaded upon a guide screw 53 that extends through the bracket and contact piece. Each stationary contact piece and associated bracket are mounted upon a base 60 of insulating material as by screws 58, 5|, and binding posts 59, 52 for the electric wires are provided in the stationary contact piece and bracket. Desirably each contact piece 48 is provided with a contact point 56, which makes contact with a corresponding contact point 56 on the stationary contact piece 51.

With the notches and high parts of the several star wheels disposed as above described, two of the movable contact pieces are engaged in the notches of the star wheels thereby effecting contact between the contact points of said two movable contact members with the contact points of the two associated stationary contact members, thereby closing the breaks in the circuits controlled by said contact pieces. and the other movable control pieces are held out by the high parts of the associated star wheels, thereby separating the contact points of those movable contact pieces and their associated stationary contact pieces. Each time the star wheels are rotated one step this order is reversed so that the previously closed contacts are opened and the previously opened contacts are closed.

The circuit. transferring mechanism just described functions as a circuit transferring switch, and acts to transfer the circuit from one pilot switch first to one motor and then to the other and so on, when connected up as illustrated in Fig. 4. Briefly the terminals at one end of the contactors are connected to two-"pole pilot switches A, B and the other terminals'of the contactors are connected to the starters N, B as shown and the pilot-switches are cross connected and connected to the starters, which are connected to the main lineE. For a fuller-description of the circuits referencemay be had to the parent patent above referred to. The connec tions may however be varied as desired and the contactors may be used to open and 'close'circuits for any electrical mechanism to which the control mechanism is applicable.

. In the'operation of the control mechanism, when pressure is set up in one pipe, (for instance pipe NJ), as a result of the starting of motor A and pump A by the closing of pilot switch A'-', the diaphragm I! will 'be expanded, thereby raising the yoke 22 and compressing-the spring 21, thereby lifting the pawl 39 to the tooth of the ratchet wheel 40 next above the one with which it was previously engaged and setting the yoke in position for actuating the ratchet wheel. When the pressure or the level of the liquid in the tank has been restored the pilot switch A opens, and stops the motor A. The pressure in the pump A and pipe I0 between the pump and check valve w and in the pipe l3 and diaphragm I! quickly returns to static pressure and the spring 21 thereupon moves the yoke and therewith the stem 34 and pawl 39 downward, turning the ratchet wheel 40 one step and thereby partially rotating the notched discs 41 one step and transposing the circuit from the motor A to motor B so that the next time pilot switch A is closed, motor B will be started and diaphragm 18 will be expanded and when the motor stops, the yoke will again actuate the transfer switch. The pilot switch B is set to operate at a higher pressure or at a higher level than the switch A so as to start an idle pump in case the running one is unable to do the work re quired of it.

I claim as new and desire to secure by Letters Patent:

1. Control mechanism for a switch, comprising in combination, a plurality of independently operable pressure actuated devices, each connected with a source of variable pressure supply, a switch throwing element, a motion transmitting element, which is common to both pressure actuated devices and is directly moved in one and the same direction by either of said pressure actuated devices, whereby said motion transmitting element is set into active position without actuating the switch throwing element, and means operating in opposition to said pressure actuated devices for actuating said motion transmitting element, whereby to actuate the switch throwing element.

2. Control means for a switch, comprising in combination a switch throwing element, a plurality of independently operable pressure actuated devices, each connected with a source of variable pressure supply, motion transmitting means which is common to both pressure actuated devices and which is directly moved in one and the same direction by said pressure actuated devices, whereby said motion transmitting means is set into active position without actuating the switch throwing element, and resilient means operating in opposition to said pressure actuated devices for actuating the motion transmitting means, whereby to actuate the switch throwing element.

3. (Lontrol mechanism for a switch, compris ing in combination a plurality of diaphragms, each connected-with a source of variable pressure supply, a switch throwing element, motion transmitting means whichis common to both diaphragms and which is directly moved in one and the same direction by either of said diaphragms, whereby said motion transmitting means is set into,activ e position without actusting theswitch throwing element, and means operating in opposition to the diaphragms for actuating the -motion transmitting means, whereby to actuate the switch throwing element.

4. Control means for a rotary switch throwing element of a switch, comprising in combination a plurality of independently operable pressure actuated devices, each connected to a source of variable pressure supply, motion transmitting means which is common to both pressure actuated devices and which is directly moved in one and the same direction by either of said pressure". actuated devices, whereby said motion transmitting means is set into active position Without actuating the rotary switch throwing element of the switch, and means operating in opposition to said pressure actuated devices for actuating the motion transmitting means, whereby to actuate the rotary switch throwing element.

5. Control means for a switch, comprising in combination a switch throwing element, a plurality of independently operable diaphragms, each connected with a source of variable pressure supply, motion transmitting means which is common to both diaphragms and is directly moved in one and the same direction-by either of said diaphragms, whereby said motion transmitting means is set into active position for actuating the switch throwing element, and resilient means operating in opposition to said diaphragms for actuating the motion transmitting means, whereby to actuate the switch throwing element.

6. Control means for a rotary switch throwing element of a switch, comprising in combination a plurality of independently operable diaphragms, each connected with a source of variable pressure supply, motion transmitting means common to and independently moved in one and the same direction by either of said diaphragms, whereby said motion transmitting means is set into active position without actuating the switch throwing element, and means operating in opposition to said diaphragm for actuating the motion transmitting means whereby to operate the switch throwing element.

7. Control mechanism for an actuated element, comprising in combination a plurality of independently operable diaphragms, each connected with a source of variable pressure supply, an actuated element, motion transmitting means which is common to and directly engaged by and moved in one and the same direction by said diaphragms, whereby said motion transmitting means is set into active position without actuating the actuated element, and resilient means operating in opposition to said diaphragms for actuating the motion transmitting means whereby to actuate the actuated element.

8. Control mechanism for an actuated element, comprising in combination, a plurality of independently operable, pressure actuated devices, each connected with a source of variable pressure supply, an actuated element, motion transmitting means which is common to and which is directly engaged by and moved in one and the same direction by either of said pressure actuated devices whereby said motion transmitting means is set into active position without actuating the actuated element, and resilient means operating in opposition to said pressure actuated devices for actuating the motion transmitting means whereby to actuate the actuated element.

9. In control mechanism for electric motors, pressure operated actuating mechanism for a. circuit transferring mechanism comprising a. plurality of expansible and contractible pressure actuated devices, each adapted for connection with a separate source of pressure supply, a reciprocatory yoke which is common to and which is directly engaged and moved in one and the same direction by either of said pressure actuated devices, and switch actuating means operated by said yoke.

10. In control mechanism for electric motors, pressure operated actuating mechanism for a circuit transferring mechanism comprising a plurality of expansible and contractible, independently operable, pressure actuated devices, each adapted for connection with a separate source of pressure supply, a reciprocatory yoke common to both pressure actuated devices, each of said pressure actuated devices being arranged to move the yoke in one direction only, a switch actuating shaft, a ratchet wheel thereon and a pawl carried by said yoke and engaging said ratchet wheel.

11. In control mechanism for electric motors, pressure operated actuating mechanism for a circuit transferring switch, comprising a plurality of independently operable diaphragms, each adapted for connection with a separate source of pressure supply, a reciprocatory yoke common to both diaphragms and adaptedvto be moved in one and the same direction by either diaphragm, resilient means to actuate the yoke in the opposite direction, and a double throw switch actuated by said yoke.

AUGUSTUS C. DURDIN, JR. 

